Haoxin Lv

Fresh peanuts (Arachis hypogaea L.) are highly susceptible to Aspergillus flavus contamination, leading to rapid quality deterioration. Lactic acid bacteria (LAB) are well established as natural agents for preserving agricultural products and inhibiting pathogenic microorganisms. However, their efficacy against A. flavus in fresh peanuts remains underexplored. This study evaluated the efficacy of Pediococcus pentosaceus DB12 cell-free supernatant (P. pentosaceus DB12 CFS) in mitigating A. flavus contamination in fresh peanuts, integrating assessments of quality parameters, microbial indices and untargeted metabolomics. Results demonstrated that P. pentosaceus DB12 CFS effectively mitigated A. flavus-induced deterioration in fresh peanuts, as evidenced by improved retention of color, textural hardness, and weight during storage. P. pentosaceus DB12 CFS also significantly reduced total number of mold colonies and mildew rate. Furthermore, it suppressed electrolyte leakage and malondialdehyde accumulation, inhibited peroxide and acid value elevation, and minimized the degradation of soluble sugars and sucrose. Metabolomic analysis further revealed the activation of phenylalanine metabolism, stilbenoid, diarylheptanoid and gingerol biosynthesis, and glutathione metabolism, thereby enhancing disease resistance in fresh peanuts. This study not only establishes the efficacy of P. pentosaceus DB12 CFS in mitigating postharvest A. flavus contamination in fresh peanuts but also provides a foundation for developing safe and efficient biocontrol technologies.

Rice storage under suboptimal conditions leads to rapid quality deterioration. In this study, effects of low-temperature (LT, 20 °C) combined with nitrogen-controlled atmospheric conditions (NCA, 95%) on physicochemical properties, nutrient, mycotoxins and metabolites of rice during 180 d storage were comprehensively evaluated, to explore a potential preservation technique for rice. The LT + NCA treatment significantly inhibited the accumulation in free fatty acid value, malondialdehyde and electrolyte leakage, while maintaining higher catalase activity, lower amylose content and better pasting properties (higher breakdown, lower final viscosity and setback). Crucially, mycotoxin accumulation remained within safe limits across all groups, with LT + NCA showing the lowest levels. Metabolomics analysis identified 653 metabolites, with LT + NCA significantly modulating pathways related to carbohydrate metabolism (e.g., promoting raffinose accumulation while inhibiting the pentose phosphate pathway) and amino acid metabolism (enhancing glutathione metabolism and suppressing arginine biosynthesis). These metabolic rearrangements reduced oxidative damage, stabilized membrane integrity, and preserved cooking quality. Therefore, LT + NCA could be a superior strategy for delaying oxidative stress, maintaining nutritional and cooking quality, and ensuring the safety of stored rice.

Grain is highly vulnerable to contamination by fungi during storage, leading to reduced product quality and substantial economic losses. Lactic acid bacteria (LAB) have the potential to be used as antifungal agents; however, strains aimed at inhibiting stored grain molds remain limited, and the inhibitory mechanisms require further investigation. To solve this problem, 71 LAB strains were isolated from various samples. Among these, 17 strains exhibiting inhibitory activity against A. flavus, A. niger and P. citrinum were selected using a dual-layer plate assay. Based on morphological characterization and 16S rRNA gene sequence analysis, these strains were classified as Weissella cibaria, Pediococcus pentosaceus, and Lactiplantibacillus paraplantarum. Further investigations involving pH adjustment, catalase, and proteinase K treatments confirmed that organic acids were the primary antifungal substances in LAB cell-free supernatant (CFS). HPLC quantification identified acetic acid, malic acid, lactic acid, phenyllactic acid and citric acid contained in the CFS. Antifungal assays verified that acetic acid and lactic acid exhibited the strongest inhibitory effects against P. citrinum and A. flavus, whereas phenyllactic acid and acetic acid demonstrated the most potent suppression against A. niger. These findings established a theoretical basis for the application of LAB CFS in grain storage.

Higher moisture content in wheat benefits processing but impairs storage stability. Current research on quality changes in high-moisture wheat under varying storage temperatures remains limited. This study systematically evaluated wheat with 14% moisture content stored at 15 °C, 20 °C, 25 °C, and 30 °C over 180 d, assessing quality parameters, mycotoxin levels, and fungal community composition. Results indicated that wheat stored at 15 °C and 20 °C maintained stable storage and processing quality. Meanwhile, the concentrations of aflatoxin B₁, deoxynivalenol, and zearalenone in wheat across all storage temperatures remained below their respective regulatory limits of 5.00 μg/kg, 1.00 mg/kg, and 60.00 μg/kg. No visible mold appeared in wheat stored at 15 °C, 20 °C, or 25 °C for 180 d, whereas initial mold characteristics emerged at 30 °C. Fungal community analysis revealed that at 15 °C and 20 °C, the dominant genus shifted from Bipolaris to Cladosporium, while at 25 °C and 30 °C, it rapidly transitioned to Aspergillus. Although fungal richness showed no significant differences, diversity indices varied notably across storage temperatures. These findings provide a theoretical basis for the safe storage of high-moisture wheat.

Sweet corn is highly susceptible to infection by Fusarium graminearum (F. graminearum) and Fusarium verticillioides (F. verticillioides) during storage, which substantially compromises its nutritional quality and economic value. However, the specific effects of F. graminearum and F. verticillioides on sweet corn quality during postharvest storage remain poorly understood. This study systematically explored the effects of F. graminearum and F. verticillioides infection on sweet corn quality by evaluating the changes in color, hardness, weight loss rate, malondialdehyde (MDA) content, surface fungal spore count, soluble protein content, and soluble sugar content. Results indicated that the critical time points for visible deterioration were 24 h post-inoculation for F. graminearum and 36 h for F. verticillioides. Compared with the control group, both infections caused significant darkening of kernel color and a marked increase in surface fungal spore counts. Notably, F. verticillioides infection was associated with a significant increase in MDA content, indicating enhanced oxidative stress in infected kernels. These findings elucidate the mechanisms of pathogen-induced quality degradation in sweet corn and provide a scientific basis for preserving and enhancing the value of agricultural products and ensuring food safety.

Sweet corn is highly susceptible to infection by Fusarium graminearum (F. graminearum) and Fusarium verticillioides (F. verticillioides) during storage, which substantially compromises its nutritional quality and economic value. However, the specific effects of F. graminearum and F. verticillioides on sweet corn quality during postharvest storage remain poorly understood. This study systematically explored the effects of F. graminearum and F. verticillioides infection on sweet corn quality by evaluating the changes in color, hardness, weight loss rate, malondialdehyde (MDA) content, surface fungal spore count, soluble protein content, and soluble sugar content. Results indicated that the critical time points for visible deterioration were 24 hours post-inoculation for F. graminearum and 36 hours for F. verticillioides. Compared with the control group, both infections caused significant darkening of kernel color and a marked increase in surface fungal spore counts. Notably, F. verticillioides infection was associated with a significant increase in MDA content, indicating enhanced oxidative stress in infected kernels. These findings elucidate the mechanisms of pathogen-induced quality degradation in sweet corn and provide a scientific basis for preserving and enhancing the value of agricultural products and ensuring food safety.

In recent years, as two globally recognized green grain storage technologies, CO₂-modified atmosphere (CO₂) storage and temperature-controlled (TC) storage have gained prominence. However, research on their integrated application remains limited. This study monitored quality dynamics and microbial activity in rice stored for 360 days under CO₂ + TC versus conventional storage (control), with analyses conducted at stratified sampling points (upper, middle, and lower layers). Compared to conventional storage, CO₂ + TC preserved rice color more effectively, while retarding the increase in fatty acid value and the decline in brown rice yield, head rice yield, and germination percentage. Furthermore, CO₂ + TC storage effectively suppresses the proliferation of Fusarium and Aspergillus, thereby retarding aflatoxin B1 (AFB1) accumulation by inhibiting fungal metabolic activity. Non-targeted metabolomics analysis further verified that CO₂ + TC storage enhanced rice antioxidant capacity and disease resistance by modulating amino acid, carbohydrate, and linolipid metabolic pathways. This technology effectively maintained nutrient retention (e.g., amino acids and proteins) and delayed quality deterioration in stored rice. These findings elucidated the underlying mechanism of CO₂ + TC on rice quality, offering a novel perspective for grain storage technology.